Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

readOnlyHint=true already declares the safety profile, so the description only needs to add context. It does add that a reason is returned when the name is unavailable, but says nothing about rate limits, whether it also validates name format/reserved words, or whether the result is cached.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single short sentence with the resource and the return condition front-loaded; no filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter read-only check with full schema coverage and no output schema, the definition covers the essential purpose and hints at the failure payload. Only the input-format tolerance and any name rules are left unstated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the parameter already documents both accepted forms ('my-agent' or 'my-agent.agentborn.org'). The description restates the fully-qualified form but adds no new constraints (e.g. allowed characters, length) beyond the schema's maxLength.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('check') and resource ('<name>.agentborn.org') plus the availability outcome, so an agent can tell exactly what the tool returns. It does not need sibling differentiation because none of the listed siblings (get_post, lookup_agent, etc.) overlap with subdomain availability.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied — the natural reading is 'call before registering a subdomain' — but the description never states when to use it, when not to, or any prerequisite such as naming rules. No alternative tool is named, though no close alternative exists among the siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.